Mold extractor control



July 2, 1940 F..HAGIEMEYER ,459

5 Sheets-Sheet 1 Patented July 2, 1940 UNITED sr- T-es- PATENT orrica MOLD EXTBACTOR CONTROL Henry F. Hagemeyer, Chicago, 111., assignor, to

Castings Patent Corporation, a corporation of Illinois Application October 26,v

15 Claims.

My invention pertains to automatic control mechanism for mold extractors such, for exam ple, as that disclosed in my application Ser. No. 213,165 filed June 11, 1938, entitled Mold extraLc tors, or in my Re. Patent 21,-046 issued April 11,

1939, for Apparatus for producing molds.

Such-mold extractors ordinarily include two gripping orholding heads, one of which is recip rocable toward and away. from the other. Such heads maybe, for example, a magnetic head to hold an iron matchplate or mold form, and a vacuum head to engage a surface of a mold, which latter may be of the gypsum base type.

, In the operation of such an extractor it is nec- 16 essary to energize the magnetic chuck, which may be either of the permanent magnet type or electromagnetic, to produce a vacuum between the vacuum head and mold surface engaged thereby,

to effect approach or closing movement of the heads, and to separate the mold from the matchplate or mold form by separating movement of the heads. Ordinarily these operations would be carried out by the use of manua controls, but I have devised mechanism whereby the com- 5 plete operating cycle may be controlled auto matically, it merelyb'eingnecessary to initiate operation of the control mechanism manually.

A typical example of an automatic operating cycle may include eflecting approach of the vacuum and magnetic heads, during such approachmovement energizing the magnetic head, at the end of such approach movement evacuating the vacuum head to grip the engaged mold surface, delaying separating movement of the heads until a proper seal has been eflected between the vacuum head and mold surface and a vacuum has been established therebetween, following such delay by a slow speed separating movement of the heads which icontinues'until after the mold a has been broken loose from the mold form, if

desired discontinuing the evacuating actionof the vacuum head .or the gripping action of the magnetic chuck or both, and following the slow separating movement of the two heads by a faster separating movement. Obviously the points in the operation at which the magnetic chuck and the vacuum head are energized and deenergized will differ according to the mechanical arrangement of the extractor parts. .For example, the

vacuum head may be reciprocable and face upward while the magnetic chuck may be stationary" and would face downward, which is the preferred arrangement. After the mold has been broken loose from the mold form, therefore, it will rest u on the vacuum head so that the vacuum may be be mounted on edge. .Also instead of having a operations necessary to form, a complete mold was, sen-n1 No. '23'l,018 (c1. 22-4'n' discontinued at any time. No additional mold support need be providedto receive the mold when the suction stops, as would be necessary with a downwardly facing, lifting vacuum head. It the magnetic chuck is deenergized,-however, 5 supplemental mold form supporting means must be provided, or else the mold form must be supported by the operator when the magnetic chuck releases it. v

, The positions of the heads may be. reversed, if 10 desired, the vacuum or mold supporting head, being on top and facing downward while the magnetic chuck will be beneath the mold supporting head and face upward. In this case when the vacuum head releases the mold it must either be supported by the operator or by a simplemental support, whereas the-magnetic chuck may be deenergized and the mold form will still be supported thereby. Not only may the positions of the mold supporting and moldform sup-, porting heads bereversed as described, but either the upper or the lower head may be movable and the other stationary, or both may be movable.

Moreover it is not necessary that theheads be,

disposed in a horizontal position, forthey may.

linear movement they may, swing toward and away from each'other about a fixed axis, one or both thereof moving along an arcuate path. Holding means other than a magnetic chuck and a vacuum head may be-employed which may involve different types of energizing and control mechanism.' In allthese installations, however,

certain fundamental requirements must be observed. The two heads, one to grip the mold and vthe other to grip the mold form, must approach each other, break the bond between the mold and mold form, and then separate.

The principal object of my invention isto 4 accomplish automatically the movement andextracting cycle.

More specifically it is an object to accomplish automatic approach of mold'form holding means and mold holding means, to engage both of such means respectively with a mold formand a mold contained therein, and thereafter to eflect sepa-' ration or such two means to remove the mold from the mold form.

An' incidental object action operation between-the approach of the two holding means and the initiation of their separating movement, to enable such 'hoidinl meansto obtain a firm grip upon the mold and mold form prior to such separation.

a to provide a delayed 'butlon of the holding action over substantially the whole surface of each head will be accom-- Dllshed.

\Another object is to provide such features in an automatic control the mechanism of whichis dependable, yet which will afford the requisite precision of operation. As has been pointed out, the control mechanism must be sumciently flexible to be adapted by one skilled in the art to various types of'mold extractors and similar machines. I have illustrated in the drawings, therefore, an exemplary control system the operative principles of which may be I adapted to various types of extractor and to afford operations which differ in minor particulars. The novel features of my control system are deflned in the claims. K

Fig. 1 is a fragmentary side elevation view of an extractor to which my automatic control may be adapted.

Fig. 2 is a fragmentary transverse section taken on line 2-2 of Fig. 1 illustrating stop mechanism for positioning a mold form.

Fig. 3 is a side elevation view of the control block. 1

Fig. 4 isa bottom plan 'view of the control block of Fig. 3.

Fig. 5 is a top perspective view of the control block shown in Figs. 3 and 4.

' Fig. 6 is a rear elevation view of a modified control block switch arrangement.

Fig. 7 is a fragmentary plan view taken on line 1-1 of Fig. 1 showing the positioning of control switches engaged by a reciprocable head.

Fig. 8 is a fragmentary side elevation view of the control switch arrangement of Fig. 7.

Fig. 9 is a representative control system electrical circuit and piping diagram.

Fig. 10 is a diagram showing that section of the wiring in the upper, right portion of Fig. 9 on an enlarged scale, and I Fig. 11 is a perspective view of the extracto showing the switches mounted thereon.

In my application Ser. No. 213,165, referred to above, it has been pointed out that an accurate guide mechanism must be provided for the reciprocating head. Preferably the mold gripping head and the mold form gripping head have relative linear movement, for often attached cores project into the matchplate beyond the general parting surface of the mold section. Any tilting movement or 'weaving ofthe movable head and mold will cause binding, and lateral stress will be exerted on such attached cores which will break them off, Even where precisely linear movement is accomplished there must be no sudden jerk, for such unevenness of movement sometimes causes the mold cores to break off although started from the pattern. These considerations apply whether the mold be of the gypsum base type or be made of sand or other fragile material. V -My control mechanism has therefore been designed particularly for extracting from a mold form a fragile mold without subjecting it to any shock, while atthe same time performing the ex f tracting operation entirely automatically. The. 75.

accuse A matchplate, or other form, but that illustrated is an integral matchplate and upstanding flask rim. The proper guiding operation must, of course. be

apart from the automatic control mechanism.

' When a gripping arrangement other than a positive mechanical holder is employed, such as a magnetic chuck or vacuum head, a firm engagement of the part to be gripped thereby must be accomplished, and a su'iflcient time delay be provided to enable a proper grip to be effected. In order to prevent fracture of the mold by too violent an operation in separating it from the. mold form, a very slow feed should be provided at the initiation of the separating movement of the heads, which later may be converted into a fast feed. An intermediate speed between the slow and fast speeds may also be utilized, if d red. Change from the slow to the next fas feed should not be accompanied by a jerk. for the time of change will occur before the mold cores have accomplished by the structure of the machine 1 been fully withdrawn fromthe pattern and hence L effectively employed to produce an automatic controlling operation for an extractor which will operate in the manner discussed. As adapted to an extractor of the type shown in Figs. 1 and 11, indicated at E, the control mechanism may include a hydraulic operating system coupled with an electric control shown diagrammatically in Fig. 9. In this particular form the extractor has a magnetic chuck M adapted to grip the mold form and a vacuum head V which will grip a surface of the mold. While any reciprocating mechanism may be employed a hydraulic cylinder I in which a piston I llreciprocates is suitable. This piston carries a piston rod II which is connected to the vacuum head V. The magnetic chuck M mounted above, the vacuum head is stationary and isprovided with guide ways or flanges! to receive a base plate B of a mold form or flask F as shown in Figs. 1, 2 and 11. At the endfof one of the ways is secured a spring stop" which projects beyond the guiding surface of the ways sufficiently to engage the end of the base plate to stop it in the proper position with relation to head V for extraction of the mold. The plunger of an electric solenoidor any suitable mechanical stop'may be substituted for the mechanism illustrated. With the flask or mold form F thus positioned in registry .with the vacuum head V fluid may be admitted into the lower end of the cylinder I to raise the piston i0, and thus to engage the vacuum head with the exposed surface of the mold in the mold formF. While either liquid or gas may constitute the operating fluid, the foflner is preferable', light oil operating satisfactorily.

M. After a vacuum has been established between the vacuum head and the mold surface the two heads maybe separated to break the mold loose from the mold form. The initial separating .movement should be very steadyand at a slow rate so that the fragile mold is not subjected to shock. when the bond is broken the separating designation mold form includes any pattern. movement should continue at a fairly slow rate is f untu the mom is wellclear ur ne whereer suctionjor for-any longer than is absolutely necessary, forv the removal of water from the .moldoccasioned thereby tends to' distort the mold cavity. particularly in a )direction' perpendicular. tothe parting surface of the mold and the vacuum head. My control mechanism is therefore adapted, where a vacuum head is em-' ployed, 'tofievacuate it as late as possible in the operating cycle and to terminate the evacuation almost ,as-soonas the mold is started from the mold form.

A- typicahautomatic control arrangement is illustrated -:in Fig. 9.' A liquid under pressure, supplied to cylinder I through conduit 3, is stored in a tank 30,- being forcedthereinto from a supply tank 3| by1a pump 32. A pressure relief valve 33 in a bypassfrom tank 30 to tank 3I' insures that the pressure in tank 30 will remain constant. 'Themotorl which drives pump 32 may be either;

continuously operable, manually operable, or automatically operable, to maintain the pressure of the tank within the limits of a desired pressure difierential. Tank 3| is always under atmospheric pressure being vented at 34. A valved conduit connecting the two tanks for the purpose of equalizingthe liquid level therein, and a drain for each tank, should be provided as shown,

From the tank 30. fluid under pressure is supplied-to the pressure conduit 3 which may be placed in communication with conduit 35 to admit fluid to the lower end of cylinder I. Solenoid valve 40 of the normally closed type controls the flow from pipe 3 to pipe 35.. The solenoid of this valve must therefore be energized in order to initiate upward movement of the piston I in the cylinder I. During such upward movement thenormally closed solenoid valve 4!. controlling communication, between conduits 36 and 31, is also energized for discharge of fluid from the upper end of cylinder I into supply tank 3i.

When the head V is pressed firmly against the mold and is in sealing engagement therewith piston l0 will cease its upward movement and the liquid pressure will-build up in thelower end of cylinder I, conduit 35 and air or gas dome 38. Any gas, of course,will act as a compressible medium in the dome to retardthe increase of liquid pressure. when the pressure has built, up to a predetermined value the pressure 40 and H, as will be explained hereafter, to prevent a further increase of pressure in the air.

- dome 3a and to shut the exhaust connection with the upper end of cylinder I preparatory to initiation of separating movement of'the two heads. After the piston reaches the end of its outward movement, wherein the vacuum head moved therebyis pressed tightly against the exposed surface'of the mold, there will be a. short delayprior to initiation of the separating movement to enable the vacuum to build up in head V to afford-a firm suction grip on the mold. This delayed action is accomplished by an air or gas dome 39 which decreases the rate of pressure increasein conduit 36 to a value sufllcient to -with such end had been opened. A quantity oi incompressible liquid is therefore sealed in the lower portion of cylinder I and conduit 35,.fur-

ther compression of the gas in dome 38 afiording slight relief.

Piston It will not move downward, therefore, despite closing of valve 4I and supply of liquid under pressure through 43 until an escape for the liquid from beneath the piston has been aiiforded. For this purpose a pressure relief valve 44 is provldedin a bypass between conduit 35 and exhaust conduit 31, which will be opened when so the liquid in the lower endof cylinder, l is subjected to apredetermined pressure by the liquid above'piston I0 exerting a slightly higher pressure thereon. Obviously, in order for the pres: sure controlled switch 42 to break, its operating pressure must be lower than that for which valve 44 is set, or otherwise as the pressure builds up in conduit at the end of the head's upward movement-liquid would be bypassedto exhaust conduit 3'! through valve 44 and the pressure 30 never could reach that required to actuate switch 42. It ispreferred that the pressure in the lower end of cylinder I be not relieved at the end of the, 'pistons outward stroke but that at least the first part of the inward movement take place against 1 such pressure. R.eliei' of this liquid pressure tends to cause a settling of the piston which aifords too violent a jerk-of the vacuum head and mold. This is especially pronounced when the pressure is relieved after pressure has been built up on the upper side-oi the 'piston. e

A further factor contributing to the delay in initiation of separating movement oithe heads is the utilization of a small metering orifice, either of fixed size or variable as afforded by a needle .55 valve 43, greatly restricting initial flow of liquid from pressure conduit 3 into conduit 36. Im-p mediately after valve M has closed the only communicatlon with conduit 36 is afforded through this restriction. The further and primary func- 60 tion of this metering orifice is to afford very slow downward movement of the vacuum head. in-

coupled with a gradual increase in stress corre; 55 sponding to the gradual pressure increase in the upper end of the cylinder provides a very-gentle breaking of the. bond between the mold and mold form. 3

After the piston has moved down a .very small to distance to break the mold loose from the mold. 7

form, which travel may be for various installstions from a few thousandths to an eighth of an inch or so, the normally open solenoid valve 45 is. deenergized, which, permits communication from conduit 3 to conduit 36around needle valve 43. There are now two supplementary communicating passages open between the pressufre conduit and conduit 36", one through the needle valveand the other through solenoid valve 45. 7

A further control valve 46, such as one of the. gate type, common to both these passages may control the aggregate flow through them, which in turn will control the speed of separating movement after valve 45 opens. Thisafiords a controlled intermediate speed which may persist until the mold is well clear of the mold form.

As the heads separate to-a point where the mold is entirely free from the flask or mold form,

the solenoid valve 41 of the normally open type may be deenergized by breaking of the limit switch 48," which will connect theentire flow volume of conduit 3 with conduit, through all three passages to expedite further the of separating movement of the two.' heads. Not

. only is the solenoid valve 41 opened by breaking of switch 48 but solenoid valve 45 is also deenergized thereby and moves to the open position, which relieves the pressure in the lower end of cylinder i and in conduit by establishing free communication between the latter and conduit 31 connected to supply tank 8|. Prior to opening of valve 49 a fairly high pressure,

.preferably'about 45 pounds,- has been maintained in .conduit 35 despite downward movement of piston III, by bypassing fluid through pressure relief valve 44 from conduit 35 to conduit as previously explained. Valve 44 may, of course, be set to maintain in conduit 35 during such movement any pressure less thanthat. in conduit I, desired. The maintenance of such pressure in the lower end of cylinder'l holds the vacuum head up at the end of its upward movement until pressure has been built up -in the upper end of cylinder i. as described heretofore, thus afiording the desired time delay during which the vacuum is built up between the vacuum head and the mold surface, and preventing any sudden settling of the piston is until after the mold is well clear of the mold rorm', such as at the time switch 48 breaks. A settling action will occur at this point-as valve 49 opens,

but it will not injure the mold which is then entirely freed from the mold form. All the solenoidvalves of the control mechanism have now been deenergized, leaving ,all the pressure fluid deenerfgization of valve 45, which is of the normally open type, after the piston in has moveddownward only a very short distance from its up-' permost position, somewhere between a few thousandths and about an eighth of an inch;

depending upon the characteristics of the mold being withdrawn from the mold form andother considerations of each particular installation. Breaking of the solenoid circuit may be effected by means of a switch 5 of the normally open push button type carried by a block so (see Figs. 3, 4 and 5) slidable upon a post P, which may be 'part of the extractor. proper or may be supplied only for this purpose Within the term normally open push button type switch I include any which by movement of an engaging member in a direction away from. the switch will be operated to break the solenoid circuit. Switch 5 will be selected according'to the travel of the head desired before breaking of the switch. The block 55 will be slid upward along post P by a switch engaging member 5|,car'ried by the vacuum head V or some part moving therewith, by engagement of such member with a switch operating member I! which will liold' the switch in the'contacting position during its upward movement."- some A r l a amnesia.- tion mechanism or equivalent holding means such as a spring 53 surrounding a bolt-54 secured upon the post P should be provided to hold the block stationary relative to the post under the force of gravity acting thereon. when the member 5| starts to move downward away from the switch as the separating movement of the heads is initiated, the switch operating member 52 18,8Iadually released until the switch breaks contact, at which timethe solenoid valve will be deenergized by breakingof its circuit. The switch 5 y moving up against it, but it is preferable to eflect closing of this switch to initiate operation of the entire control mechanism by manually sliding the block downward by grasping a handle .55 until the member 52 engages a fixed stop 55 which may be secured to the post 50. This mechanism also serves as a safety switch, for if it is raised either from stop 55 or from member 5| during upward movement of the head circuits of solenoid valves '40. 4| and 45 at least will be deenergized so that Since it is desirable to maintain'evacuation of t closed by the reciprocating member 5| the vacuum head for the least possible length of time, breaking of the control switch I may also be used to terminate its evacuationf Before the head reaches the bottom of its travel the mold should be freed from it by supplying air under pressure to'the head to raise, the mold slightly therefrom. This operation may be accomplished by a momentary contact switch 5 which will operate a three way air .solenoid'valve 55 to supply compressed air to the head The switch should make contact by movement in only one direction so that valve 50 will not be moved when the vacuum head moves upward. The air may be supplied to the head V through the sameconduit 5i asthat by which the head is evacuated, as shown, or through separate pipes, the vacuum conduit 52 being closed when the air supplyconduit is open.

Thisreversal of head connection from the vac-.

the vacuum conduit after a certain vacuum has been attained should be provided, for beside main-- taining the vacuum for the least possible time it is also desirable to utilize minimum amount of vacuum. A water trap 54 should also be included in-conduit 52 to remove moisture sucked from the mold, which otherwise would be passed on into the vacuum pump 55. A drain including a check valve 55 will remove the water from the tank or trap 54. Duration of the evacuation may be controlled by starting and stoppingthe pump 55, which is efiected by the circuit shown, or by employing a further normally closed solenoid valve in conduit 52 which will be energized to evacuate the head V.

The switches 5 and 45 may be mounted on the frame of the extractor as shown in Figs. 7, 8 and '11, if desired, being positioned adjacent to the path of movement of the reciprocating head to be engaged by parts of the extractor moving in con- Junction'with such head. A roller arm ofswitch 5 may be positioned to engage a pin 51 projecting laterally from the vacuum head. A roller mounted on a-swingable arm 45' ofswitch 45 may engage the side of the vacuum head to close the switch as the head moves up, and to release it as the headmoves downward-below the switch for breakmsfihe circuit.

A vacuum control Altering vertical pol timil 15 Figs. 9 and 10. is an exemplary wiring diagram which may be employed to connect these various elements together to obtain the desired operation.

It will be appreciated, howeven that the wiring may vary considerably according to the desires oi one skilled in the art and still .obtain substantially the same operation by employing equivalent mechanical elements. In the diagram illustrated, a 110 volt alternating current supply is employed in conjunction with a master relay 1 and a secondary relay I0, the latter being primarily. dependent upon operation or the pressure controlled switch 42. A third relay'll may be provided to operate a magnetic switch for energizing motor 12 which drives the vacuum pump 85. r

Such an arrangement will cause the motor to start when the vacuum head is to be evacuated and to be stopped when the evacuation is-to be terminated. As previously suggested, an alter-- native construction may include a continuously operating motor, or one controlled other than automatically; and an additional normally closed solenoid valve in vacuum conduit 82. Such solenoid valve would be operated by relay H instead of the motor 12 being operated thereby.

With the wiring arrangement illustrated the operation of my automatic systemwill be initiated by pushing sliding block 50 downward until switch operating member 52 is pressed against stop 58 which eiIects closing of switch 5. Relay 1 will thereby be energized, and since switch 42 is not under pressure and hence will be closed relay l likewise will be energized. The armature contacts closed thereby will energize the solenoid valves 40, 4|, 45, 41 and 49 and the electromagnetic chuck M, to which current is supplied from a rectifier. 18, but the vacuum motor l2'will not be started. The circuit may be altered to delay energization oi. the magnetic chuck until near the end oi the heads approach movement if desired. With the solenoid valves energized, liquid under pressure will be supplied to the lower end of cylinder land the upper end of this cylinder will be connected to the exhaust conduit 31 so that the vacuum head V will be raised. During this upward movement switch engaging member will engage switch operating member 52 when it is in switch-closed position and wiilxraise it I from stop 56 while still holding the switch in closed position, sliding block 5il upward along post P. When the head reaches its uppermost position and stops, the pressure will increase in conduit 35, which in turn will raise the pressure of the gas in dome 38 and in the Bourdon tube or switch 42 to cause this switch to break.

When pressure controlled switch 42 breaks, relay is deenergized-although relay 1 remains energized. Deenergization of relay 10 starts the vacuum pump motor 12 by a circuit through a normally closed armature contact of relay Ill and a normally open armature circuit of relay I which is still being held in the contacting position. Also solenoid valves Land 4| willbe deenergized thereby and will close. There will be no movement downward of the vacuum head V, which will be held in its upper position by. the liquid now sealed inthe lower end. of cylinder land in conduit 35, until after an increase in pressure. predetermined by the setting of pressure relief valve 44, has been established in the upper end ofthe cylinder. Initially pressure liquid will and the pressure in the upper end oi? the cylinder will increasegradually because of the action or air dome 39 retarding such increase. When the pressure has finally reached a value which will force piston l0 downward and cause liquid to flow from conduit through valve 44 into conduit 31, the vacuum head V will commence its downward movement to break the bond between the mold and mold form. This will be accomplished, as previously stated, after very slight separating movement of the two heads. At the end of a small predetermined movement switch engaging member 5| will have receded from switch operating member 52 a distance suflicient to release switch 5 for breaking the switch operating'member being now well above stop 56 and the switch no longer being held in the closed positionby engagement therewith, which will effect deenergization of master relay I.

Breaking of the armature circuits of relay I only be supplied through the metering orifice 43, 1

will in turn cause deenergization of solenoid valve 45 and relay H controlling vacuum motor", so that simultaneously a greater flow of pressure liquidwill be admitted to the upper end 0! cylinder l and the evacuation of vacuum head V will be terminated. It will be noted that the liquid in the lower end of cylinder l and inconduit 35 will still remain under pressure, but 'because of the increase in rate of supply of pressure fluid to the upper end of the cylinder the speed .at which the heads. separate will be increased to intermediate speed. This operation shown in Fig. 1. 'Deenergization of these solenoid valves, allowing -them both to open, will effect i'ast downward movement of the head Visince valve 41 allows unrestricted flow otpressure liquid to'the upper end of cylinder-l and opening otvalve 49 eiiects communication of conduit 35 with conduit 31 to relieve the pressure in the lower end of the cylinder. All the solenoids have now been deenergized as wellas the mag! netic chuck and vacuum head. The piston I will continue its downward movement untilit reaches its limiting position.

During the latter part of the heads downward travel switch 6 will be momentarily closed which will reverse three-way valve .60 to supply air under pressure, to such head. This will lift the mold slightly to prevent its sticking to thehead and to enable it to be removed easily by the operator. 4 f

At the completion of this cycle of operations switch 5- will remain in the open position and sliding block 5|! will be held in the raised position to which it was moved by upward movement of member 5|. In order toagain initiate operation 01 the control mechanism for another operating cycle it is merely necessary to slide block 50 down post? until switch 5 is again closedby engagement of member 52 with stop 58. In Fig. 6 is'shown a modified form or push button switch arrangement to enable adjustment of the amount of separating movement of the heads which will cause breaking of switch 5. In this variation, to the switch operating member 52 of. Figs. 3,4 and.5 is attached a" spring or flexible leaf '1 pivoted on sliding block 50 at I8. Its other end engages a vertically adiustable limit stop screw I. as it is pushed up ward by switch eng ging member ll. After the switch is closed 1 of spring leaf I! will merely flex it until it engagesstop screw 5! in the position in which it,

is set. As member ll recedes from block 50 leaf 10 II will flrst unbend, and as it approaches the Almost immediately thereafter member 5| will leave leaf '1, as shown in broken lines. Ob-

viously the farther down screw so projects the smaller will be the travel of head V before switch 5 breaks. Stop it is positioned to engage member ll opposite switch operating member 52 the same as in the form of Figs. 3, 4 and 5.

As myinvention I claim: 1. In a mold extractor, a head movable to extract a mold from a pattern, a piston rod connected to said head, a piston carried by said rod, a fluid cylinder receiving said piston, fluid supply means connected tosaid cylinderior forcing said piston and rod outward, fluid supply means connected to said cylinder for forcing said piston and rod inward in the mold extracting direction, control means actuated by the increased pressure in 1 said flrst fluid supply means at the end of the pistons outward movement for initiating opera-- tion of said second fluid supply. means, and means operableto retard the rate of pressure increase in said flrst fluid supply means at the end of said pistons outward movement. 4

2. ma mold extractor, a head movable to extracta mold from a. pattern, a piston rod connected to said head, a piston carried by said .rod, a liquid filled cylinder receiving said piston, means i connected to said cylinderior supplying ,liquid underpressure thereto to iorce said piston and rod outward, means connected to said cylinder for supplying liquid under pressure thereto to force said piston and rod inward in the mold ex-' tracting direction, control means actuated'by the increased pressure in said flrst liquid supply means at the end or the pistons outward movement for initiating operation of said second liquid supply means, and a gas dome communicating with said control means, containing gas compressible by liquid from said first liquid supply means, for retarding the rate of pressure increase in such means to pressure suflicient to operate said control means.

3. In a moldextractor, a head movable to ex- 8- tract a-mold from a pattern, a piston rod connectfluid cylinder receiving said piston. fluid supply means connected to said cylinder for forcing said piston and rod outward, fluid supply means connected to said cylinder for forcing said piston and 00 rod inwardin the mold extracting direction, control'means actuated automatically at the end oi means after initiation oii'ts ,operation'by said control means.

4. In a moldextractor, a headmovable to extract a mold from a pattern. a .piston rod connected to said head, .a piston carried by said rod, a liquid-fllled cylinder receivins'said piston, means to said cylinder for supplying liquid under pressure thereto to force saidpiston and rod outward, means connected to said cylinder for supplying liquid under er pressure on the free end broken line position shown switch 5 will break.

ed to said head, a piston carried-by said rod, a

pressure thereto to force said piston and rod inward in the mold extracting direction, valve means actuated automatically at the end of the pistons outward movement for initiating operation oisaid second liquid supply means, and a gas dome communicating with said second liquid supply means between said valve means and said cylinder, containing gas-compressible by liquid from said second liquid supply means, for retard- *ing the rate of pressure increase in such means to pressure sufllcient to move said piston after initiation of its operation, and thereby delayinginitiation of inwardmovement of said piston and rod 4 I 5. In a mold extractor, a head movable to extract a mold from a pattern, a piston rod connected to said head, a piston carried by said rod, a fluid cylinder receiving said piston, fluid supply means connected to said cylinder for forcing said piston and rod outward, fluid supply means connected to said cylinder for forcing said piston and rod inward in the mold extracting direction, a

metering oriflce for limiting the rate of flow through said second fluid supply means at the initiation of its operation, an air dome for delaying therate of pressure increase in said second fluid supply means to pressure suflicient to move ,said piston after 'initiation of its operation, and means operable automatically to by-pass said metering oriflce to give substantially unrestricted D flow through said second fluid supply means by partial inward movement of said piston rod.

6. Automatic control mechanism for a reciprocating gripping head, comprising means operable to move the head in one direction into gripping I position, andto return it in the opposite direction, delayed action means operable to postpone; for a predetermined time interval, initiation of movement of the head in such opposite direction, and means operated by movement of said head B into gripping position to eflect gripping operation 01' the head while said delayed action means is in operation. v f

7. Automatic .control mechanism for a reciprocating, vacuum, mold grippin head, comprising means operable to move the head in one direction into gripping position, and to return it. in the opposite direction, and evacuating means energized to withdraw air from the head by movement of said head into mold D sition, thus to eflect a suction grip on the sur face or the mold engaged by the head. I

8. Automatic control mechanism torn reciprocating vacuum mold gripp ng head, compris ing means operable to move the head in one direction into mold en aging position, evacuating means for the head energized by engagement of the head with a mold disposed in mold engaging pomtion, said flrst means being further op erable to return the .head in the opposite direction,- and delayed action means operable to postpone initiation or movement or the head in such opposite direction until after a flrm suction grip on the engaged surface of the mold has been eitectedby the vacuum head. 65

9. A mold extractor, comprising a magnetic chuck, a vacuum head, means for efl'ecting relative approach and separating movement of said chuck and vacuum headyahdautomatic control means operated prior to initiation of separating '7 movement of said chuck and vacuum head to eirect energisation or said magnetic chuck and evacuation of said vacuum head, and operated during separating movement of said chuck and V vacuum head to eii'cct dtion of said to magnetic chuck and to terminate .evacua said'vacuum head. v

10. The combination or "claim 9, and means operable during separating movement 01 the on of chuck and vacuum head andsubsequent to termination of the evacuation of said vacuum head to blow air into said vacuum head to loosen the mold from such head.

11. A mold extractor, comprising a mold form holding head, a, mold gripping vacuum head.

means for effecting relative approach and separating movement of said heads, and automatic control means operated prior to initiation oi sep arating movement of said two heads to eflect evacuation of said vacuum head, including means operable after very slight separating movement of said heads to terminate evacuation or saidvacuum head. k

12. A mold extractor, comprising a mold form holding head, a mold gripping vacuum head,

means operable to effect relative approach movement of said heads, and to flect relative separating movement of said heads at a rapid rate, automatic control means operated prior to initiation of separating movement of said two heads to effect evacuation of said vacuum head, including evacuation control means operable after very slight separating movement of said heads to terminate evacuation of said vacuum head, and said first means being operable, prior to initiation of separation of said heads at a rapid rate, to eflect relatively slow separatingmovement otthe heads from initiation of separating movement at least until operation of said evacuation controlmeans to terminate evacuation of said vacuum head.

13. A mold extractor, comprising a mold form.

holding head, a mold gripping vacuum head,

means for effecting relative approach and separating movement of said heads, and automatic control means operated prior. to initiation of separating movement 01 said two heads to eflect evacuation of said vacuum head, and including a push button switch to terminate evacuation of the vacuum head,'and switch engaging means t engageable with said switch .in closed position prior to initiation of separating movement 01' the heads, and movable to effect opening 0! said extending parallel to the course of movement of said heads, a block, slidable along said guide member, a switch engaging member, one of said members being movable with one of said heads, a control circuit energizable to effect evacuation of said vacuum head and deenergizable to terminate evacuation of such head, a normally open push button switch in said control circuit engageable, in closed position, between said block I and said switch engaging member, and thereafter operable to slide with said block along said guide member during the approach movement of said heads, and meansto hold said block stationary with respect to said .guide member upon initiation of separating movement of said heads, for relative recession of said switch engaging member from said push button switch to release it for breaking said control circuit.

15. A mold extractor, comprising a mold form holding head, a mold gripping vacuum head,

means for eiiecting relative vertical approach and separating movement of said heads, a vertical guide rod, a block slidable along said guide rod, friction spring means operable to hold said block in any position on saidrod against the force of gravity thereon, a control circuit energizable to efiect evacuation of said vacuum head and deenergizable to terminate evacuation of such head, a normally open push-button switch in said control circuit carried by said sliding block, a stop on said rod engageable with said switchto close it by downward movement o1 said block, and a switch engaging member movable with one of said heads and engageable with said push button switch in closed position, and

thereaiteroperable to slide it in closed position with said block along said guide rod'upward from said stop during the approach movement oi-said heads. I w a HENRYF: HAGEMEYER. 

